A. Field of the Invention
The present invention relates to cotton candy machines, and in particular, how the rotating or spinner head assembly of a cotton candy machine is detachable and re-attachable from and to the machine.
B. Problems in the Art
Cotton candy making machines have a relatively long history. They have retained their basic form. They typically utilize a rotating spinner head assembly. That head assembly rotates at substantial speeds (e.g. several thousand RPM) by connection to an electric motor in the base of the machine. An electric heating element is in the head. Therefore, electrical power must be provided to the spinning head. This usually requires something like a slip ring assembly to transfer electrical power to a base of the machine to the spinning spinner head. A raw cotton candy, sugar-based solution is poured into the head. The rotation of the head throws the sugary solution by centrifugal force out to the walls of the head and through screens or openings to basically create the fluffy cotton candy caramelized sugarized strains. Those strains are caught in a bowl that surrounds the head.
U.S. Pat. No. 3,036,532 and published U.S. Patent Application US2002/0062743 A1 illustrate several examples of these types of cotton candy machines. Details regarding them can be seen in those patents, which are incorporated by reference in their entireties herein as background information.
There are several interesting and subtly-related factors that come into play with these types of cotton candy machines. One is the relatively extreme rotational speeds of the head. These machines are utilized in a variety of settings; sometimes using workers that are not experts with these machines. The connection of the rotating head to the motor shaft must be robust. Even though the spinner heads are relatively lightweight, spinning at such high RPM creates substantially forces. These forces not only can include centrifugal force but, because of manufacturing tolerances, substantial vibration forces in different directions.
Additionally, the electrically-energized heating element in the head must maintain electrical connection to an electrical power source while the head is rotating. Thus, a variety of ways have been developed to try to reliably do so. Several are described in detail in the incorporated by reference patent and published patent application listed earlier. For electrical connections using conducting rings and brushes, the head-to-motor-shaft connection must be not only robust but also ensure that electrical power to the head is maintained when operating.
But moreover, the general operational environment of these machines creates rather unique issues. The sugary substance involved with cotton candy is messy, coats components, and can make it important to frequently clean the machine. It is desirable to restrain the substance to the bowl around the rotating head. It is desirable to be able to clean the bowl as well as the head. To do so thoroughly generally requires the ability to remove the bowl and the head from the machine. This can be antagonistic to having a robust connection between head and rotating shaft and a good electrical connection between head and remainder of the machine.
For example, over time the screens or small openings in typical cotton candy machine spinner heads get clogged with the cotton candy solution and must be cleaned out. One conventional way to attach a head to a motor drive shaft is with an Allen screw, bolt or pin or other set screw. It can be difficult for non-mechanical persons, or persons not familiar with the machine, to find and then remove this fastening mechanism to remove the head and reattach it in the secure manner.
A further consideration is that not only is it desirable that the head be detachable, but that both detachment and reattachment be as easy and efficient as possible. It is also desirable that reattachment provide high confidence to the operator that the reattachment is secure. It is not desirable to rely on an operator's mechanical skills to ensure good reattachment. There are also issues with expired conducting surfaces and motors when the head is removed from the base.
FIGS. 1-3 illustrate a typical present way of attaching a cotton candy machine spinner head to the drive shaft of the motor. The lower end of adapter head 4 is bolted to spinner head 2 (e.g. see bolt 11 which clamps spinner head 2 to adapter head 4 by tightening it into threaded bore 12 in the upper end of adapter head 4. This allows spinner head 2/adapter head 4 to be attached and detached from motor shaft 5 by slideably fitting the bottom end of adapter head 4 over the upper or distal end of motor shaft 5.
Attachment and detachment of the head 2 is achieved by tightening or loosening a single Allen or set screw 7 with an Allen Wrench tool 9 through a small blind hole 3 in housing or base 1. The head 2 can be marked for the orientation of the setscrew 7 (see visual dot 10 placed on the outside of head 2 in FIG. 1; this dot 10 can be lined up with the blind hole 3 in base to try to line up set screw 7 with blind hole 3 so that it can be accessed by Allen Wrench tool 9 through blind hole 3). However, there are difficulties with this arrangement. Aligning dot 10 with blind hole 3 is an approximation. It may not indicate consistent exact alignment. Thus, the user may have to find set screw 7 with wrench 9 by trial and error, as it is not possible to get a good visual view of set screw 7. Also, mark 10 might no longer be there or may not be visible after the machine is used for awhile. To remove head 2 then has to be done through even more trial and error to find setscrew 7 in blind hole 3. Note also that if the Allen wrench or other tool is lost or misplaced, it may be very difficult if not impossible to detach or attach the head at least until another appropriate tool is obtained.
Note that motor shaft 5 can have a flat spot 6 to receive the setscrew 7, to help ensure torque is transferred from motor 8 to the head 2. As can be appreciated, if said screw 7 is not firmly installed, forces generated by the high RPM rotating or spinner head can create vibrations or other forces which attempt to try to separate the rotating or spinner head from its shaft or which cause the motor shaft to slip relative the head. This could cause malfunction or at least poor operation. Even relatively small separation might also affect electrical connection between electrical brushes of a slip ring assembly in base 1 (see, e.g., FIGS. 2 and 11) and conducting rings on the head. Also, over time, the setscrew can dig into the motor shaft or can strip in its threads which create risk of malfunction or poor operation.
FIG. 3 shows in section view setscrew 7 and its relationship with motor shaft 5. It also illustrates the relationship of electrical brushes with conducting rings on the head 2.
The single set screw is central to this state of the art detachable head assembly.